Gender most doesn't mean nation, and it doesn't mean family, and yet that's what the word 'genus' meant. And genus is still a word, and it's a grouping in taxonomy, which keeps the 'family' definition, but has nothing to do with birth or nations.
We've picked, chosen, and modified definitions throughout history. It's the reason dictionaries have *had* editions for centuries. Because things *do* get rewritten when definitions change. And when they do, the old one remains until it's no longer used. Words like stock, cell, and locomotive had more definitions tacked onto them in the past 300 years. We're not just making things up. And updated definitions are a thing too. We defined the word 'planet' differently 30 years ago than we do now, for example.
'Libtards' aren't the only people who rewrite dictionary entries. Language is a constantly evolving thing, and it has been for millennia.